Bore wear Sprint engine

[cleverusername]

I think I am homing in on the source of the noise, my best guess is piston slap. I have set of new TR7 pistons laying around, so I stripped the rings off one and used it as a gauge to check the bores. Basically inserting it into each bore and checking the gap using a feeler gauge. This was what the little book of lies said to do. Is that correct?

Anyway the results were not good, with every bore failing the check. With a modern engine the sensible option would be a new block or boring out the pistons to the next size up. However with no good blocks about and oversize pistons costing silly money, the best option seems to be a re-sleeve.

Which alas doesn't look to be cheap but I can see few other options. Does anyone have any ideas of cost and where is the best place to get work done?

[SprintV8]

Barnum Engines keep coming up on my Facebook page.
Putting Ductail liners in Cosworth Blocks.

https://barumenginesltd.com/services/

David Moore in Godstone does a fair amount of rare Classic engines.
He’s currently doing a couple of Classic Mini engines and heads for a friend.

https://www.davidmooreengineering.com/

[cliftyhanger]

How about finding a good 1850 block (unlinered) and get that bored out?

[xvivalve]

In 2009 I had a Sprint block taken back to standard bore to suit the new pistons I then had. Along with lightening and balancing all moving parts, and a crank grind, it cost me £600 in machining costs and £80 plus VAT for the liners.

Given I recently paid about £170 inc VAT for just a crank grind, I'd say you should add significantly to that figure for today's costs...

[cleverusername]

How about finding a good 1850 block (unlinered) and get that bored out?

That sounds like an idea but before I attempt it can I check that it is possible? Can you bore out any 1850 block and will the head properly line up with the mounting holes in the block?

[cliftyhanger]

I know somebody who is building a sprint engine by doing just this. But I am sure others will confirm it is possible. The key is to find an original/unlinered 1850 block, I understand that the "new" blocks that are/were available were all linered, but those fitted when the cars were new were not.

[xvivalve]

My plan for today is removal of an 1850 engine from a 1975 car which has stood since the 1990s…the block is surplus to my requirements…I had it turning over briefly 10 days ago, but then it stopped…location: Stourport on Severn

[cleverusername]

My plan for today is removal of an 1850 engine from a 1975 car which has stood since the 1990s…the block is surplus to my requirements…I had it turning over briefly 10 days ago, but then it stopped…location: Stourport on Severn

Hi, that could be a life saver, could I PM you this evening about it? We are about to head out to enjoy the sun.

[xvivalve]

Yes, feel free...but it will now be the next session before it's out; heat and corrosion slowed me down!

[cleverusername]

Yes, feel free...but it will now be the next session before it's out; heat and corrosion slowed me down!

No worries, this is along term project.

[gmsclassics]

Yes, I can confirm your idea works very well. The last race engine I built, back in 2013, started life as an 1850 auto. We bored out, used standard size pistons. We also use the crank from the 1850, which having lived its life attached to the auto box, was in exceptionally good condition, still on original big ends and mains. Never had any issues subsequently with the engine (and it revved to 7000).

Geoff

[Philip Larmour]

I agree with Geoff.

A number of my race engines have started life as 1850 blocks. Just make sure the water gallery between the pump and block is opened up. Our rule of thumb was you needed to be able to put two fingers through the gallery.

Philip

[Mad Mart]

There's a couple of 1850 blocks for sale here:

https://forum.triumphdolomite.co.uk/vie ... 12&t=37415

[xvivalve]

I think the concentric circles are just a register from the fire ring in the gasket; I seemed to be able to polish it out with 1500 grit wet and dry:



No sign of liners from below:





Anyone consider otherwise?